That's anecdotal though... How many of the current okupas happen in other's primary residence? Would be considered trespassing in those cases and a lot easier to get rid of them, compared to the other cases.
It's literally not. Maybe if you'd actually experience the situation yourself here you'd know about the differences. But alas, hard to understand from the outside I suppose.
Invading a property people actively live in = The police comes quickly to throw the invaders out
Invading a property that been empty for years where the owner refuses to either rent out or sell it = Harder to get them out, for obvious reasons.